It is to be understood that the description in this part only provides some background information relating to the present disclosure, which may or may not constitute prior art.
Nowadays, a lithium ion battery is a new green chemical power source. Compared with conventional nickel-cadmium batteries and conventional nickel hydrogen batteries, lithium ion batteries have many advantages such as higher voltage, longer cycling life and higher energy density etc. Ever since the Japanese company Sony launched the first generation lithium ion batteries, lithium ion batteries have been developed rapidly and applied in various kinds of portable devices. The negative electrode in the conventional lithium ion battery comprises graphite carbon material. However, the theoretical specific capacity of the carbon material is only about 372 mAh/g. Therefore, further improvement of the capacity of the lithium ion battery is restricted.